North American Journal of Fisheries Management 26:206–212, 2006 [Management Brief] American Fisheries Society 2006 DOI: 10.1577/M05-121.1 Estimates of Tackle Loss for Five Minnesota Walleye Fisheries PAUL RADOMSKI,* TOM HEINRICH,THOMAS S. JONES,PAT RIVERS, AND PHIL TALMAGE Minnesota Department of Natural Resources, 500 LaFayette Road, St. Paul, Minnesota 55155, USA Abstract.—Lead poisoning in waterbirds from ingestion of found elsewhere (Pokras et al. 1993; Scheuhammer and lead fishing items may be a growing problem. There are few Norris 1995; Daoust et al. 1998). studies that quantify tackle loss for recreational fisheries. Lead poisoning from ingestion of lead fishing items Tackle loss from large recreational lake fisheries in Minnesota may be a growing problem. Common loons, mute is unknown. The objectives of this study were to determine swans, and trumpeter swans Cygnus buccinator appear tackle loss for five large lake fisheries targeting walleye Sander vitreus in Minnesota by means of creel surveys and to to be susceptible to lead poisoning (Blus et al. 1989; estimate recent cumulative losses. Mean rates of tackle loss Environmental Protection Agency 1994). Lead poison- were low: 0.0127/h for lures, 0.0081/h for large sinkers, ing from lead sinker ingestion was first reported in the 0.0057/h for small sinkers, 0.0247/h for jigs, and 0.0257/h for United Kingdom for mute swans (Simpson et al. 1979). hooks. Many anglers lost no fishing tackle on a fishing trip. These findings resulted in a ban on lead sinkers in The estimated total loss of tackle for the five water bodies in England and Wales in 1987 (Kirby et al. 1994). The the summer of 2004 was 214,811 items. Over 100,000 lead- incidence of lead poisoning cases in mute swans then based items were estimated to have been lost, representing fell and the population increased, yet blood lead levels about 1 metric ton of lead. Assuming 2004 lead tackle loss rates, estimates of cumulative lead item loss for Lake of the in mute swans remain high, probably from long-lost Woods and Mille Lacs and Rainy lakes from 1983 to 2004 lead fishing sinkers and weights (Perrins et al. 2003). In were 285,000 (SE ¼ 8,800), 1,033,000 (SE ¼ 39,700), and North America, Locke et al. (1982) was among the 211,000 (SE ¼ 8,400) items, respectively. In critical wildlife earliest to report lead poisoning in common loons from areas with high angling effort or high tackle loss rates, fishing sinkers. Perry (1994) compiled over 300 determining the impacts of lead tackle on wildlife would be incidences of sinker ingestion in over 20 wildlife prudent, and prohibiting the use of lead tackle may be species. In Canada, Scheuhammer and Norris (1995) necessary. found 46 incidences of lead poisoning from lead sinker ingestion in 8 bird species and later revised those There is now greater awareness of the direct and numbers and noted 381 incidences of ingested lead indirect effects of fishing on fish and wildlife and their habitat. Recent studies on the physical disturbances fishing sinkers in North America in 28 wildlife species from commercial fish trawlers and trappers on benthic (Scheuhammer et al. 2003). Pokras et al. (1993) state habitat have found substantial reductions in habitat that ingestion of a single lead sinker or lead-headed jig complexity (Auster and Langton 1999). Recreational is a lethal dose for a loon. Franson et al. (2003) anglers also diminish natural resources through the loss examined loons that died in rehabilitation centers or and inappropriate disposal of fishing tackle or gear. were found dead in the wild and noted that ingested Wildlife have been injured or killed as the result of lead sinkers were found in 11 of 313 birds (3.5%). entanglement or ingestion of fishing tackle. Entangle- There are few studies that quantify tackle loss for ment with fishing line is known to have killed brown recreational fisheries. We are aware of only one pelicans Pelicanus occidentalis, mute swans Cygnus unpublished study in North America on estimates of olor, and bald eagles Haliaeetus leucocephalus (Zim- tackle loss and abundance of lead sinkers in sediment. merman 1976; Birkhead 1982; Schreiber and Mock Duerr (1999) interviewed 859 anglers from 14 sites in 1988). In Minnesota, entanglement accounted for 19% the United States and found that anglers, on average, and lead poisoning from lead sinker ingestion for 17% lost 0.18 sinkers per hour, 0.14 pieces of fishing line of adult mortalities of common loons Gavia immer per hour, and 0.23 hooks and lures per hour. Tackle (Ensor et al. 1992). Higher rates of mortality for loss in large recreational lake fisheries in Minnesota is common loons as a result of lead poisoning have been unknown. The objective of this study was to determine tackle loss for five large lake fisheries that target * Corresponding author: [email protected] walleye Sander vitreus in Minnesota and to estimate Received July 26, 2005; accepted September 23, 2005 recent cumulative losses. These lakes are also impor- Published online February 3, 2006 tant waterbird lakes; therefore, estimated lead densities 206 MANAGEMENT BRIEF 207 in lake sediments may be useful information for wildlife managers. Methods Creel surveys were conducted on Rainy Lake, Namakan Reservoir, Leech Lake, Mille Lacs Lake, and Lake of the Woods (Figure 1). Rainy Lake and Namakan Reservoir are located on the border of Minnesota and Ontario, Canada. These waters are infertile with little aquatic vegetation, and much of the shoreline is rocky and irregular. Walleye is the primary species of interest for anglers, although northern pike Esox lucius, sauger S. canadensis, smallmouth bass Micropterus dolomieu, and black crappie Pomoxis nigromaculatus are also sought and harvested. Leech Lake is in north-central Minnesota. Although the maximum depth is 48 m, about 80% of the lake is less than 11 m deep. Most anglers seek walleye, yellow perch Perca flavescens, northern pike, or muskellunge E. masquinongy. Mille Lacs Lake is the second largest lake entirely within Minnesota. The saucer-shaped basin of Mille Lacs Lake has a maximum depth of 13 FIGURE 1.—Location of five lakes in Minnesota where m and averages 9 m. Offshore habitats include sand estimates of tackle loss were determined during walleye and mud flats, rock reefs, and a few small, exposed recreational fisheries, summer 2004. islands. Rocky areas, where tackle may be more likely to be lost, comprise less than 10% of the total lake Completed-trip interviews were obtained by inter- surface area. The fish community is primarily com- viewing anglers returning to shore. In addition to the posed of walleye, yellow perch, northern pike, and standard questions posed to anglers, creel clerks asked muskellunge, and these are also the principal species anglers whether they lost any fishing tackle. If anglers targeted by anglers (in decreasing order of effort). Lake lost tackle, the creel clerk followed up with questions of the Woods’ surface area is 384,997 ha, of which to determine what and how much tackle they lost that 128,287 ha are managed by the State of Minnesota, including Muskeg, Big Traverse, and Little Traverse day. Anglers were asked how many lures, jigs, hooks, bays. Big Traverse and Muskeg bays are largely devoid split shot sinkers (all sinkers less than 11 g), or large of structure and islands, while Little Traverse Bay is sinkers were lost. Lead tackle items included lead- more characteristic of the Ontario water of Lake of the headed jigs, split shot sinkers, and large sinkers. Woods, along with numerous islands and reefs. Estimates of angler effort and tackle loss were Average depth of Big Traverse Bay is 7 m. The calculated following the methods described by Bind- summer fishery is dominated by anglers seeking man and Mach (1997), which incorporate standard walleye (.80% of the anglers). creel survey calculation procedures (Pollack et al. Nonuniform-probability creel survey designs were 1994). Tackle loss calculations followed the same used, where each creel survey began on May 15, 2004, procedures as estimates of fish harvest. For lead items, the opening of the fishing season, and extended to the estimated loss in weight was calculated by September or October (Table 1). Creel strata included multiplying the estimate of loss by the prevailing time periods (usually half-month periods). Each time weight of the item used for the given fishery. strata was also split into weekdays and the weekend or For Lake of the Woods, Mille Lacs, and Rainy lakes, holidays. Sampling days were split into two non- the cumulative loss of lead tackle items from 1983 to overlapping time periods such that the bulk of the 2004 was estimated from summer estimates of angler fishing day was sampled. Angling effort was de- effort from past creel surveys multiplied by the 2004 termined from aerial boat counts (Rainy Lake, estimate of lead item loss per angler effort for the lake Namakan Reservoir, Leech Lake) or number of boats (Table 2). The 1983–2004 time period was selected landing within a designated stretch of shoreline (Mille because annual summer creel surveys were conducted Lacs Lake and Lake of the Woods). Most angling on on these lakes during this time period. Namakan these fisheries in the summer was from a boat. Reservoir and Leech Lake did not have annual 208 RADOMSKI ET AL. TABLE 1.—Measures and creel survey statistics for five Minnesota lakes for which estimates of tackle loss were determined during walleye recreational fisheries, summer 2004. Standard errors